Refrigeration



Jan. 30, 1945. B. REISTAD I REFRIGERATION Filed Nov. 25, 1941 Z INVESTOR ATTORNEY QPatented Jan. 30, 1945 aarmcam'rron new Belated, Stockholm, Sweden Application November 25, 1941. Serial No. 420352 Iii-Germany December I, 1910 My invention relates to refrigeration, and more particularly to refrigeration systems employing evaporation of refrigerant fluid in the presence otan auxiliary inert fluid. 1

It is an objectof the invention to provide a refrigeration system of this type in which circulation of an absorption liquid is carried out by vapor lift action and generated vapors are rec tifled by heat transfer out of physical contact with the absorption liquid below the surface level of liquid in the absorption liquid circuit, the contact being prevented by ressure of the vapor as will be more fully understood upon reference to the following description in connection with the accompanying drawing in which the single figure shows more or less diagrammatically a re frigeration system embodying the invention;

A generator i has a heating flue ll into the v lower end of which is directed the flame oi a gas burner l2. Around the lower part 01' flue II and in heat exchange relation therewith there is a pipe coil IS. The upper end of coil I3 is connected by a vapor lift conduit ll to the upper part of generator Ill. The lower end of coil I3 is connected by a conduit IE to the lower end of a pipe it. The upper end or pipe I6 is connected to one end 01' the outside passage "of a triple heat exchanger i8. The topoi generator I0 is connected by a conduit ill to the upper end of .pipe it. Pipe It may be a downturned extension of the outside tube of the heat exchanger as, as shown.

The other end of passage ll of the heat ex changer i8 is connected by a conduit 26;, a liquid trap 2i, and a-conduit 22 to the upper end of, an

air cooled condenser 23. The lower end of condenser Ed is connected by a conduit 2G to the upper part oi. an evaporator coil 25 located in a refrigerator storage compartment 26. The liquid trap 2i is formed by a vessel connected at its top by conduit 22 to the condenser 23. Conduit 20' has an upward loop 29a, ofwhich one leg is connectedto the heat exchanger it. and the other leg projects downward into the lower part of vessel 29.

The upper end of evaporator coil 28 is connected by a conduit 21!, a gas heat exchanger 28, and a conduit 29 to. a vessel 3%. The lower end of an absorber coil 88 is connected to vessel 39. The upper end of absorber coil 8! is connected by a conduit 32, gas heat exchanger 28, and conduit so to thelower end of evaporator coil 25.

The lower end of condenser 23 is connected by and a conduit 36 to conduit 21 in the evaporator-.

absorber circuit.

The bottom of vessel is connected by a conduit 31, and the intermediate passage 38 of the heat exchanger l8, to the upper part of pipe II. The conduit forming passage 38 projects downward and is open in'the upper part of pipe ll. The upper end oi absorber coil 3| is connected by a conduit 39,the inner passage 40 of heat exchanger I8, and a conduit thtothe lower part of generator It. In the drawing the conduit 38, heat exchanger passarelll, and conduit ii are shown as a single pipe.

The system vjust described is evacuated and charged with a solution of refrigerant fluid in an absorption liquid such as, for instance, a thirty percent solution 01 ammonia in water, and an auxiliary pressure equalizing fluid such as hydro gen gas which is charged, into the system at a pressure such that the total pressure in the system will be the condensing pressure of ammonia at a fairly high room tem: rature.

Operation oi. the system is caused by lighting the burner l2. Operation of the burner It may be thermostatically controlled responsive to a temperature condition 'aile'cted by the evaporator 25, as known. The burner l2 by way of flue ll causes heating of liquid in pipe coil l3 and generator l0. Heating 01' liquid in these parts causes expulsion of ammonia vapor from solution. Vapor expelled from solution in coil l3 rises through conduit ll raisingvtherewith liquid intothe upper part of generator lit. The level. of liquid rises in generator Id until it reaches the level of the connection of conduit 39 to the upper end 01" absorber coil 3| whereupon liquid flow takes place through the remainder of theabsorption liquid circuit by gravity. The liquid flows from the bottom of generator to through conduit 4|, heat exchanger I8, and conduit 89 into the upper end of absorber coil iii The liquid flows downward through absorber coil 3! absorbing through conduit 89 into the upper part'of pipe I8. Vapor in generator l9 and conduit i8 de-. presses the surface level of liquid in conduit 15 so that the vapor bubbles through liquid inithe a part of conduit 36. a conduit 35, a vessel 35. .55 upper part of pipe it and enters the outer pac orr ca 7 sage I I of the heat exchanger 18. Vapor flows from heat exchanger l8 through conduit 20, vessel 2|, and conduit 22 to the condenser 23. Vapor in conduit depresses the surface level of liquid in the leg of this conduit connected to vessel 2| so that vapor bubbles from the end of conduit 20 upward through liquid in vessel 2!. The pressure of vapor in conduit 20 above that in the rest of the system is the weight of the column of liquid from the end of conduit 20 in the bottom of vessel 2| to the surface level of liquid in the vessel 2|. This vapor pressure causes depression of the surface level of liquid in-heat exchanger 18 and the upper end of pipe l6 below the surface 1 vel of liquid in absorber vessel 38 a distance subs aacially equal to the height of said liquid column in vessel 21. This depression of liquid keeps the outer heat exchanger passage ll clear of liquid so that vapor therein is in heat exchange relation out of physical contact with liquid flowing in the intermediate heat exchanger passage 38. This heat exchange causes condensation of water vapor in passage-ll and the condensate flows by gravity to the absorption liquid circuit by way of the upper end of pipe l6.

Refrigerant vapor condenses to liquid in condenser 23. The liquid flows through conduit 24 into the upper end of evaporator 25. The liquid flows downward in evaporator coil 25, evaporating and diffusing into the atmosphere in the evaporator. The evaporation of liquid produces a. refrigeration efiect for cooling the refrigerator compartment 26.

The resulting mixture of hydrogen gas and refrigerant vapor flows from the upper end of evaporator coil 25 through conduit 21, heat exchanger 28, and conduit 29 to absorber vessel 30. The mixture flows from vessel 30 upward through absorber coil 3| in which the refrigerant vapor is absorbed into solution as described. Weak gas flows from the upper end of absorber coil 3! through conduit 32, heat exchanger 28, and conduit 33 back to the evaporator 25.

Any non-condensible gas such as hydrogen which finds its way to the condenser 23 escapes from the condenser through conduit 24, conduit 34, vessel 35, and conduit 36 to the gas circuit. Any uncondensed ammonia vapor from condenser 23 flows through conduit 34 into vessel 35 and displaces gas from this storage vessel through conduit, 36 into the gas circuit so that the pressure in the system rises until complete condensation of ammonia vapor takes place in the condenser 23. 7

Various changes and modifications maybe made within the scope of the invention asset forth in the following claims.

What is claimed is:

1. An absorption refrigeration system having a circuit for inert gas, a. circuit for absorption'liqui'd including a generator and an absorber and in which liquid is caused to circulate by vapor lift action, a rectifier for refrigerant vapor located beneath the surface levels of liquid in said generator and said absorber arranged to be cooled by liquid in said circuit and communicating with said circuit fordrainage of condensate from the rectifier into the circuit, and a conduit for conducting vapor from said rectifier, said conduit forming a liquid column forming trap arranged to impose a resistance to vapor flow such that the necessary vapor pressure to overcome such resistance is sufficient to bar entrance of liquid from said circuit into said rectifier.

2. An absorption refrigeration apparatus having a gas circuit including an evaporator and an absorber, an absorption liquid circuit including a generator and said absorber, a vapor lift for causing flow of absorption liquid in said absorption liquid circuit; a condenser connected to deliver liquid refrigerant to said evaporator, a conduit for vapor from said generator to said condenser including a rectifier in heat exchange with a part of said absorption liquid circuit and located below the surface levels of liquid in said generator and said absorber, and a liquid trap, said rectifier being in open communication with said circuit for flow by gravity of condensate from said rectifier into said circuit, and said liquid trap being arranged to impose such resistance to vapor flow that vapor pressure suflicient to overcome such resistance is also sufilcient to exclude en trance of liquid from said absorption liquid circuit into said rectifier.

3. A refrigeration system making use of a. pressure equalizing fluid and having an absorption liquid circuit including a generator and an absorber and in which flow of liquid is caused by vapor lift action, a heat exchanger located below the surface levels of liquid in said generator and said absorber, said heat exchanger having a part in which refrigerant vapor flows, and another part included in said absorption liquid circuit, so that refrigerant vapor in said first part flows in heat exchange with liquid in said circuit, said first part communicating with said absorption liquid circuit for flow of condensate from the vapor into the liquid circuit, a liquefier, a conduit for vapor from said first heat, exchanger part to said liquefier, said conduit including a liquid trap for resisting flow of vapor through said conduit so that the pressure of vapor in said first heat exchanger part is sufiicient to keep the surface level of liquid out of said first part. i

4. A refrigeration system employing an auxiliary inert fluid for pressure equalization and having an absorption liquid circuit including an absorber, a generator, a heat exchanger locatedbelow the surface levels of liquid in said amorber and said generator, and a vapor lift for causin circulation of liquid in the circuit, said heat-exchanger having a passage not included in said absorption liquid circuit but in open communication therewlth, a condenser, and a conduit for conducting vapor from said generator to said condenser including said heat exchanger passage and a liquid trap, said liquid trap being arranged to require an over pressure of vapor in the part of said conduit which includes said heat exchanger passage so that liquid from said circuit is prevented from entering said passage.

BENGT REIBTAD. 

